Common rail fuel injection systems for engines, particularly diesel engines, typically include at least one high pressure fuel pump, a plurality of fuel injectors, and at least one rail (or accumulator) connected between the fuel pump and the nozzles to accumulate fuel at a desired, relatively high pressure from the pump for injection by the injectors.
It is also known to utilize electronic control units to control and monitor various functions of the engine and its associated systems, including controlling fuel injectors. One such method and apparatus for comprehensive integrated engine control is disclosed in U.S. Pat. No. 5,445,128, issued Aug. 29, 1995 to Letang et al for "Method For Engine Control" and assigned to Detroit Diesel Corporation, assignee of the present invention.
It is desirable to have an electronic fuel pressure control system which is integrated with a comprehensive electronic engine control unit to eliminate duplication of control hardware, as well as to maximize the efficiency of the entire controlled system.
It is also desirable to employ a fuel pressure control method which provides closed-looped control of the fuel pressure in a common rail system, with limited inputs from other sensors, subsystem controls, or from other functional portions of the comprehensive integrated control system.
It is further desirable to employ a control system and method for obtaining and maintaining selected fuel pressures within a common rail fuel injection system which is relatively insensitive to supply voltage fluctuations in the electrical system.